Roger Ebert BLASTS Ryan Dunn for Drunk Driving

Ryan Dunn hasn't  even been dead for a day yet -- and film critic Roger Ebert is already ripping the late "Jackass" star for boozing before getting behind the wheel  ... tweeting, "Friends don't let jackasses drink and drive."

Dunn's drinking buddy claims Ryan had at least 3 beers and 3 shots before hitting the road in his Porsche.